下列计算正确的是( )
a 4•a 1=a 4
(a 3) 2=a 5
3x 2﹣x 2=2
2a 2÷3a= 2 3 a
下列运算正确的是( )
﹣2x 2y•3xy 2=﹣6x 2y 2
(﹣x﹣2y)(x+2y)=x 2﹣4y 2
6x 3y 2÷2x 2y=3xy
(4x 3y 2) 2=16x 9y 4
一个矩形的面积为a2+2a,若一边长为,则另一边长为 .
下列计算错误的是 ( )
( - 3 a b 2 ) 2 = 9 a 2 b 4
- 6 a 3 b ÷ 3 ab = - 2 a 2
( a 2 ) 3 - ( - a 3 ) 2 = 0
( x + 1 ) 2 = x 2 + 1
下列运算正确的是 ( )
a 3 · a 2 = a 6
( a 3 ) 2 = a 5
2 a 3 ÷ a 2 = 2 a
2 x + 3 x = 5 x 2
下列计算正确的是 ( )
2 a + 3 b = 5 ab
( 3 ab ) 2 = 9 a b 2
2 a · 3 b = 6 ab
2 a b 2 ÷ b = 2 b
x 2 + x = x 3
( - 3 x ) 2 = 6 x 2
8 x 4 ÷ 2 x 2 = 4 x 2
( x - 2 y ) ( x + 2 y ) = x 2 - 2 y 2
2 x 2 + x 2 = 2 x 4
x 3 · x 3 = 2 x 3
( x 5 ) 2 = x 7
2 x 7 ÷ x 5 = 2 x 2
3 x 3 - 5 x 3 = - 2 x
8 x 3 ÷ 4 x = 2 x
xy xy - y 2 = x x - y
3 + 7 = 10
下列等式成立的是 ( )
2 + 2 = 2 2
( a 2 b 3 ) 2 = a 4 b 6
( 2 a 2 + a ) ÷ a = 2 a
5 x 2 y - 2 x 2 y = 3
下列运算中,正确的是 ( )
3 y + 5 y = 8 y 2
3 y - 5 y = - 2
3 y × 5 y = 15 y 2
3 y ÷ 5 y = 3 5 y
5 ab - 3 a = 2 b
( - 3 a 2 b ) 2 = 6 a 4 b 2
( a - 1 ) 2 = a 2 - 1
2 a 2 b ÷ b = 2 a 2
m 2 · m 4 = m 8
( - 2 mn ) 2 = 4 m 2 n 2
( m 2 ) 3 = m 5
3 m 3 n 2 ÷ m 2 n 2 = 3 mn
3 x + 2 x = 5 x 2
3 x - 2 x = x
3 x · 2 x = 6 x
3 x ÷ 2 x = 2 3
x 2 + 3 x 2 = 4 x 4
x 2 y · 2 x 3 = 2 x 4 y
( 6 x 3 y 2 ) ÷ ( 3 x ) = 2 x 2
( - 3 x ) 2 = 9 x 2